Yes, you can customise the widget in the following ways:
You can change the colours of the ticket widget via the "Embed event" tab at the top of the event management page. Simply select the Main and Background colours you want and click the update button to see how the widget looks.
Marketing opt-in wording
The marketing opt-in wording can be customised by dropping your wording into the Opt in Text box and clicking update.
Enable multi-event check-out
If you have more than 1 event in your account and are using multiple ticket widgets on your website, then you can enable multi-event check-out. This will allow customers to add tickets to their basket on multiple pages across and check-out all in one go.
To enable this, on the Embed event page tick the "Enable Multi Event Checkout" option and add the link to your What's On / event listings page which is where customers will be redirected after they have added ticket to their basket and clicked the continue shopping button
To find out more about enabling donations, click here
Once you've completed your widget customisation, click the update button and you'll see your changes in the widget. Then simply copy the embed code below and add it to your website. There's more on embedding the ticket widget here